967. When the evil are being punished, angels are always present who moderate the punishment and alleviate the pains of the sufferers, but cannot take them away. For there is such an equilibrium of all things in the other life that evil punishes itself, and unless it could be taken away by means of punishment, those in whom it exists could not but be kept in some hell to eternity, for they would otherwise infest the societies of the good, and offer violence to the order instituted by the Lord, wherein lies the safety of the universe.